The material on the compact discs and the computer program listing appendix is hereby incorporated-by-reference.
The present invention relates to an embedded terrain awareness warning system for aircraft. More specifically, but without limitation, the present invention relates to an embedded terrain awareness warning system or terrain advisory system that provides visual and aural warnings of impending controlled flight into terrain, to pilots of aircraft so that recovery may be initiated.
Existing terrain advisory systems, like the Ground Proximity Warning System (xe2x80x9cGPWSxe2x80x9d), compute the altitude required for recovery based upon current flight conditions. In some GPWS, the altitude is compared to the height above the terrain (measured by a radar altimeter) and a warning is issued to the pilot when insufficient altitude remains for avoiding the terrain. This is basically a one-dimensional solution in altitude only. This type of GPWS is sometimes referred to as a xe2x80x9clook downxe2x80x9d system because the primary sensor of the GPWS is the radar altimeter. An altimeter is typically defined, but without limitation, as a flight instrument that indicates altitude above a reference level, as above the sea or ground. The radar altimeter can typically only measure the altitude directly below the aircraft, not what is in front of the aircraft. Therefore, this type of GPWS cannot protect the pilot from flight into rising terrain (i.e., mountains). In addition, the radar altimeter is not functional when the aircraft is inverted, at steep dive angles, or at high altitudes. These types of aircraft maneuvers are common when flying tactical aircraft (a tactical aircraft is typically defined, but without limitation, as an aircraft designed for, or used in, fighting operations against a hostile force either in the air or on the surface), especially in combat and military training situations. Therefore, this type of GPWS would not be useful aboard a tactical aircraft.
For a warning system to be accepted by the pilot community it must not issue any xe2x80x9cnuisance warningsxe2x80x9dxe2x80x94that is, unnecessary warnings that occur which hinder or distract the pilot when executing authorized aircraft maneuvers. Existing GPWS met the threshold for xe2x80x9cnuisance warnings,xe2x80x9d however; current systems are still nuisance prone in some areas because of the system""s inability to accurately project terrain ahead of the aircraft.
Another approach to terrain advisory systems utilizes a geographic input. In this approach representative data is stored for various geographic locations. Certain terrain advisory systems store computer representations of terrain. Typically, these systems do not store all of the irregularities of the terrain and obstacles. Instead, some current systems approximate the terrain and obstacles by a series of standard shapes. These standard shapes include simple geometric shapes such as cones, truncated cones, connected cones and other shapes. This type of system only approximates the terrain and often does not give an accurate reading or warning to the pilot, and often times gives incorrect nuisance warnings, especially at supersonic speeds (greater than the speed of sound) and in combat situations.
Certain terrain advisory systems do not provide recovery solutions or inform the pilot the type of action required to avoid terrain. This type of system requires the pilot to determine the action needed, which may take time, after which it may be too late to initiate recovery.
For the foregoing reasons, there is a need for an embedded terrain awareness warning system for aircraft. Information relevant to attempts to address these problems can be found in U.S. Pat. No. 4,433,323, 4,495,483, 4,567,483, 4,646,244, 4,684,948, 4,675,823, 4,725,811, 4,849,756, 4,857,923, 4,891,642, 4,905,000, 4,914,436, 4,947,164, 5,059,964, 5,136,518, 5,153,588, 5,166,682, 5,196,847, 5,839,080, 6,088,634, 6,092,009, 6,122,570, and 6,138,060. (None of these patents are admitted to be prior art with respect to the present invention.) However, each of these references suffers from one of the above listed disadvantages or from an unlisted disadvantage.
The present invention is directed to an embedded terrain awareness warning system for aircraft that satisfies the needs listed above and below.
It is an object of the present invention to provide an embedded terrain awareness warning system for aircraft that overcomes many of the disadvantages of currently used warning and terrain advisory systems. An embedded terrain awareness warning system having features of the present invention comprises of a signal processing component, a protection component and a pilot vehicle interface. The signal processing component is in communication with three-dimensional digital terrain elevation data; the three-dimensional digital terrain elevation data contains digital terrain. The signal processing component is able to take input data from aircraft sensors and determine aircraft velocity and aircraft position on the three-dimensional digital terrain elevation data. The protection component is in communication with the signal processing component such that the protection component is able to predict a flight path of the aircraft and overlay the flight path on the digital terrain elevation data and is able to determine if a potential controlled flight into terrain situation exists. The protection component is further able to determine a recovery flight path to avoid terrain. The pilot vehicle interface communicates with the protection component such that the pilot vehicle interface can issue to the pilot of the aircraft a warning if there exists a potential impending flight into terrain, and issue to the pilot directions for a recovery flight path solution to prevent flight into terrain. The directions for a recovery flight path solution is based on the recovery flight path to avoid terrain.
It is an object of the present invention to provide an embedded terrain awareness warning system for aircraft that predicts recovery in three dimensions.
It is another object of the present invention to provide an embedded terrain awareness warning system for aircraft that warns the pilot of flight into rising terrain.
It is also an object of the present invention to provide an embedded terrain awareness warning system for aircraft that is functional when the aircraft is inverted, at steep dive angles, at high altitudes, or during emission control conditions (radar altimeter turned off for threat avoidance).
It is also an object of the invention to provide an embedded terrain awareness warning system for aircraft that can be effectively used aboard a tactical aircraft.
It is also an object of the present invention to provide an embedded terrain awareness warning system for aircraft that does not over-predict the recovery capabilities, thus significantly reducing nuisance warnings.
It is an object of the present invention to provide a robust terrain advisory system that predicts flight in all types of terrain and all flight phases and issues warnings to the aircrew in sufficient time to successfully recover the aircraft from flight into terrain. It is another object of this invention to minimize nuisance warnings while providing this protection.
It is an object of the present invention to provide an embedded terrain awareness warning system for aircraft that integrates multiple sensor data to reduce errors and eliminate false or nuisance warnings. False warnings are, but without limitation, those warnings that are caused by erroneous data while the aircraft is not in a potential controlled flight into terrain condition. Controlled flight into terrain is typically defined, but without limitation, as a fully functioning aircraft and pilot crashing into terrain or water. This type of incident usually results when a pilot loses situational awareness or becomes preoccupied with a task.
It is also an object of the present invention to provide an embedded terrain awareness warning system for aircraft that stores all of the irregularities of terrain and obstacles.
It is an object of the present invention to provide an embedded terrain awareness warning system for aircraft, which provides visual and aural (pertaining to the sense of hearing) warnings of impending controlled flight into terrain to pilots of aircraft so that recovery can be initiated.
It is an object of the present invention to provide an embedded terrain awareness warning system for aircraft, which provides a recovery arrow on the head-up display or primary flight instrument of the aircraft and directive voice commands warning the pilot of impending controlled flight into terrain so that recovery can be initiated.
It is another object of the present invention to provide an embedded terrain awareness warning system for aircraft, which provides the pilot of the aircraft a warning of impending controlled flight into terrain and informs the pilot the type of action required to avoid the terrain.
It is an object of the present invention to provide an embedded terrain awareness warning system for aircraft that accurately models the aircraft responses, thereby, increasing the likelihood that a warning will be issued in sufficient time for successful recovery.